Technology

I wrote my Bachelor's thesis on the software that runs 5G networks.

4G (speaking about LTE) has been wildly successful since its introduction in 2009. It replaced the circuit switched network used in 2G and 3G with Evolved Packet Core, a network that delivered network packets directly to the phone using real IP addresses.

Now, a decade after 4G's release, technology has progressed a lot. What telecom companies call 5G are a collection of new technologies that are all coming out around the same time, but are mostly compatible with existing 4G phones and networks.

The big new technology is "5G new radio" (5G NR), which is a new optimized radio protocol that allows for faster speeds, lower power consumption, and the ability to use new extremely high bandwidth frequencies in the 50-400GHz range, on top of the existing 600-6000MHz range. Cellphones say that they're connected to 5G when they start speaking with the 5G NR protocol. I believe telecom companies can support 5G NR just by upgrading the cell tower antennas.

These newer antennas supporting this new radio protocol are also being built with beamforming tech, which allows towers to electronically "point" the antennas at nearby phones, improving signal.

Finally, the big upgrade underneath the surface is the migration to virtualize network functions, which is allowing telecom companies to run their networks using flexible lightweight computers inside the towers, instead of big bulky pre-built appliances in some big datacenter. This makes the network backbones faster, easier to program, and makes them cheaper for telecom companies to build out.

Wikipedia gives a bit of a summary about these features here:

https://en.wikipedia.org/wiki/5G#Technology

Lots of people getting hung up on specific details... but the actual practical benefit of 5G over 4G is simple:

5G can have an order of magnitude more devices connected at once. This will allow us to have more things connected to the network.

4G ran up against the limit to how many devices per square mile can be connected a long time ago in densely populated areas. The transition to 5G has solved the issue. It's even solved it for 4G users, since there are now less 4G users.

@Wigglet it's got more Gs

Lots of fancy math to fit more information into the same amount of radio waves.

There are two 5Gs. There is Sub-6GHz-5G and Milimetrewave 5G.

Sub-6GHz-5G operates in roughly the same frequency ranges as 4G. Radiation-wise it is pretty much exactly the same as 4G. The cell size is similar, the frequences are similar, range and object penetration are similar. What is different is that 4G was built upon 3G which was built upon 2G, which means, that 4G has very complicated and inefficient signaling and overhead compared to 5G, where they decided to declutter the protocol and make the management much easier. The main benefits of Sub-6GHz-5G are for the network operator, since it makes management so much easier. The only really meaningful advantage for the users is, that 5G allows to allocate a higher bandwidth to a single user in case no other users in the cell need it right now. This is only very rarely the case, so in most cells this won't happen often.

mmWave-5G is a different beast. It operates on frequequencies between 24-100Ghz, which is more than the max 6GHz that the otherr kind of 5G runs on. These higher frequencies are quite different. First, hardly anything else uses it, so the frequency bands are mostly empty, so you can reach incredible speeds on these bands. The problem is, there is a reason why hardly anything uses it. The range is super low (about the same range as a good wifi access point) and the object penetration is abysmal. A sheet of paper can block the 5G signal. Or a tree. Or your hand. Or your head.

So if you hold your phone the wrong way, or turn the wrong way, or have hair that covers your phone, you might not get reception at all.

So the use cases for mmWave-5G in the real world are incredibly limited, and they are usually used in a few hotspots in a larger city, just so the network providers can advertise their services as "Up to (huge number) GBit/second".

So now for the radiation argument: Both kinds of 5G are solidly inside the non-ionizing-radiation-territory, so the only thing you can do is heat something up. And heat is something you feel, so if it doesn't burn you it doesn't harm you. Other than e.g. UV radiation, which is ionizing and causes skin cancer, and yet people willingly expose themselves to UV in intensities that are 10 000x or more than what they expose themselves to 5G. They even expose themselves on purpose to UV to the point that radiation sickness (=sunburn) sets in, but the same people are afraid of 5G. Go figure.

But to really disspell the fear of 5G: Sub-6-5G is radiation-wise identical to 3G, 4G and WiFi. mmWave-5G is so weak in object penetration that it gets blocked by a piece of paper or the outer layer of the skin. And the radiation exposure is incredibly tiny.

Imagine you and I like to talk and we write each other post cards. And we send them via a local courier business run by a 16 year old who wants summer money.

4G is where we use their service so send a card each day and its consistent and works across our neighbourhood.

5G (non millimetre wave) is about the same as 4G but the courier us using an electric bike rather than their normal bike.

5G Millimetre is when this teen hires 4 other kids and they all are using go-carts to go back and forth from our houses to deliver each post card.

The up side is its fast as hell, the downside is go-carts can drive on normal roads.

Using a bike might be slower but they can use public roads and we can connect outside of our neighbourhood. Its slower but it generally works at longer ranges.

One of the biggest changes in 5g is the separation of the control and data planes, this means downloading pix of kitties doesn't interfere with phone control signals and gets everyone better bandwidth and responsiveness.

This also facilitates "edge computing", which is like a tiny clouds at the base of cell phone towers, this tech is used for super fast facial recognition and things like that where sending the data all the way to the cloud and back is a few milliseconds too slow.

I see a lot of people talking about specific parts of 5G but honestly most of them are optional and only some of them will be active at once.

"Regular" 5G uses the same frequencies as 2G, 3G, etc. The carriers will be moving more frequency ranges of older Gs to 5G as time goes on.

In general, we can send more data at once because we have better math for sending data. There's not really an ELI5 that can explain that part besides more math.

Another part is there's also more math so that the phones can take turns talking better or split up frequencies better, so they don't have to re-transmit as much.

If you're in hyper-crowded areas, they made a new frequency range that cannot go through walls, but is way faster than the regular ones that we've been using. It's only good for like sports stadiums and stuff, and you almost never use this. It's called mmwave (millimeter-wave) and you can safely ignore any marketing around it. Not many phones support it yet because it's useless 99% of the time.

4G: Fast phones. 5G: Faster phones. Neither of them can give you cancer or cause Covid or are Bill Gates mind control or whatever else the cookers are coming up with these days. The best explanation I've seen is this hilarious and educational video from ElectroBoom: https://youtu.be/i4pxw4tYeCU

Alright, more of a eli5 as I'm more folk knowledge than a scientist.

It's a narrower (more dense) wavelength.

If you think of signal, any signal, how close you are to it, the total power of that signal and the quality of your receiving gear are going to be your three major factors in "speed".

5g gains the ability to broadcast more waves iif you're close, at the expense of distance.

If you're looking to send communications further; wider (lower density) waves face less resistance. Just the same way you can seemingly get AM radio (bouncing off our atmosphere) anywhere vs FM radio (line of sight), each has a function.

You can find rural houses like mine, or the futures trades riding from the burbs to downtown with microwave (narrower than 5g) connections. They're pretty atmosphere resistant but require tuning to hit relays the size of about a soda can.

I don't think the longitudinal studies have been done on what frequencies over long periods of time produce negative results, the areas of spectrum we are working with have no real analogues in scope I'm aware of. Which is exactly why there's room to scaremonger over it.

Anecdotally I've worked a decade in an adjacent field and never heard of anyone contacting the plague.

5g is actually two separate things. One of them is just 4g again but the other is a new kind of radio that is blocked by stuff like windows and trees and needs way way more cell towers to work.

As you grow up and learn new words, you can say more with fewer of them.

Somebody else already did a pretty good job explaining it, but in case some additional information helps:

It's sort of like stepping from making couriers go hike on foot in 3G to sending couriers on mountain bikes in 4G. With 4G LTE these couriers received e-bikes and panniers (faster and more stuff to carry). The bikes are not only faster, but can also be used in all sorts of environments (road, gravel, sand, snow, ...), whether it's 4G or 4G LTE.

When we now step up to 5G, we need to distinguish 2 parts: you might here about millimiter wave or highspeed 5G and then there's the 5G sort of representing an evolution of 4G LTE. Think of the latter like this: these bikes and e-bikes that the couriers used were pretty good, but people figured the bikes could be improved, so they slapped on better tires to remove friction and make it easier for the couriers to pedal and support more weight. The person sending the postcard won't really notice much difference, but the courier will notice the difference and be able to service more people trying to send a postcard.

The highspeed/millimiter wave part on the other hand is like handing them motorcycles. Much, much faster and able to carry even more, but don't even try hiking a mountain in a street bike. They'll be really good in some environments, not really useful in others since they just get stuck after a short range.

Now regarding radio and broadcasting:

These happy information rays are sort if like yelling across a room. We can't hear it since our ears aren't made to hear this, just like our eyes can't see infrared or ultraviolet light, but your radio or TV can. Just like yelling, broadcasts can't control who can hear what is being yelled. Everyone in range will be able to hear. You just need to point your ear in the right direction, and you'll be able to pick up what's being said, you might just not know the language it's being said in.

Your mobile phone works on a similar principle. Cell towers are typically divided into sectors. Imagine 3 people standing in a circle with their backs against each other yelling in 3 different directions through speaking trumpets. While the trumpeters might hear something they each say here and there, the trumpets are really good and only yell in the direction they point. In the middle of these 3 stands a coordinator who sees you standing in the direction of trumpeter 2 and tells trumpeter 2 to yell your way. You hear trumpeter 2 telling you about the coordinator and decide to talk to this one instead of another one you can barely hear down the road.

You yell back, but different from the trumpeters, you yell in all directions (in your own language so nobody else can understand), which is why the trumpeter needs much better ears than you do. It also helps that he's sitting higher up so he can focus more on hearing you instead of road traffic or other stuff. Since you're not the only one there, the coordinator will give you all your individual times to talk and will talk to you in turn.

That's how it used to be. 4G LTE added the ability to better divide the time between different listeners, and 5G further added the ability to split sentences between different users (the beginning goes to user A, middle to user B, end to user C). You still get about the same you heard before, maybe a little more if there are fewer people in the room, but more people can now talk at the same time. For the high speed version, the trumpeter puts the trumpet down and tries to hand you a string telephone. You need to get much closer to use it, but it will be clearer and faster once you're there.

I’d recommend against discussing technical things with people who just believe random weird shit they read on the Internet. You can’t win with arguments, because they didn’t need them to believe in cancer rays in the first place.

I would explain it in terms of Wifi and speed and reach. Wifi is faster than 4G but has shorter reach. 5G is in between. That's why more antennas have to be built for 5G.